Greater numbers of antral follicles in the ovary are associated with increased concentrations of glucose in uterine luminal fluid of beef heifers

Authors: Snider, Alexandria - Alex; Crouse, Matthew; ROSASCO, SHELBY - New Mexico State University; EPPERSON, KAITLIN - South Dakota State University; NORTHROP-ALBRECHT, EMMALEE - South Dakota State University; RICH, JERICA - South Dakota State University; CHASE, CHADWICK - Retired ARS Employee; Miles, Jeremy; PERRY, GEORGE - South Dakota State University; SUMMERS, ADAM - New Mexico State University; Cushman, Robert - Bob

Submitted to: Animal Reproduction Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/11/2022
Publication Date: 3/15/2022
Citation: Snider, A.P., Crouse, M.S., Rosasco, S.L., Epperson, K.M., Northrop-Albrecht, E.J., Rich, J.J., Chase, C.C. Jr., Miles, J.R., Perry, G.A., Summers, A.F., Cushman, R.A. 2022. Greater numbers of antral follicles in the ovary are associated with increased concentrations of glucose in uterine luminal fluid of beef heifers. Animal Reproduction Science. 239. Article 106968. https://doi.org/10.1016/j.anireprosci.2022.106968.
DOI: https://doi.org/10.1016/j.anireprosci.2022.106968

Interpretive Summary: The uterine environment is important for supporting early embryonic development and alterations can lead to reduced embryonic survival. Glucose is a primary source for the developing embryo in-utero with increased concentrations observed in pregnant heifers. Heifers with increased number of antral follicles have increased uterine protein concentrations, which is suggestive of an improved uterine environment. The current study examined uterine luminal glucose concentrations and abundance of uterine glucose transporters from females with increased or diminished number of follicles. Females with increased number of follicles have greater uterine luminal glucose concentrations. This information provides insight of the impact increased number of antral follicles has on the uterine environment for improving pregnancy rates for cow-calf producers.

Technical Abstract: Increased antral follicles are associated with greater fertility and a uterine environment that is more supportive of early embryonic development in beef heifers. Glucose is a primary energy source for embryos, and glucose concentrations are elevated in uterine luminal fluid (ULF) of pregnant heifers. We hypothesized that ULF glucose concentrations and endometrial transcript abundance for glucose transporters on d16 after insemination would be greater in heifers with increased numbers of antral follicles. Heifers classified with either increased or diminished antral follicle counts were artificially inseminated following the CO-Synch protocol (d0). On d16 after insemination, reproductive tracts of heifers were collected at an abattoir to retrieve conceptuses to determine pregnancy. Uterine luminal fluid was collected, endometrium was biopsied, total RNA was extracted and glucose transporter transcript abundances were determined. Data were analyzed using the MIXED procedure of SAS with antral follicle group, pregnancy status, and the interaction as fixed effects. Glucose concentrations in ULF were greater in heifers with increased antral follicle numbers. Glucose ULF concentrations increased in pregnant heifers. Facilitated glucose transporter member 1 (SLC2A1) transcript abundance was increased in the endometrium of pregnant heifers but was not different due to antral follicle number or the interaction. Differences in uterine concentrations of glucose associated with antral follicle number could be due to another mechanism, since glucose transporters were not different between antral follicle numbers. Therefore, heifers with increased number of antral follicles have increased energy availability in the uterus to support trophoblast proliferation and function.